The Siemens 5SL4108-7RC is a SENTRON miniature circuit breaker (MCB) — 1-pole, C-curve, rated 8 A at 415 V AC, with a 10 kA breaking capacity per EN 60898.
The 8 A rating at 30 °C is the continuous current the breaker carries in a 30 °C ambient; the same 8 A is listed at AC rated value. The 10 kA breaking capacity per EN 60898 means it can safely interrupt a fault current up to 10 000 A — adequate for most residential and light commercial service entrances where the prospective short-circuit current stays under that threshold. The 1-pole design protects a single phase; for multi-phase circuits you stack identical poles.